Model : TD-W8951ND

Hardware Version : Not Clear

Firmware Version :

ISP :

I usually do my homework myself, but googled/struggled for 4-5 hours now, and I am doing something wrong and I can't define it, hence the post..

I have a Cable Internet connection and a Motorola SB6120E modem (very simple modem with 1 RJ45 port and no router ability).

I connected TD-W8951ND with a cable to the Motorola, and set the following:
Bridge Mode on, DHCP Disabled, Access Point On, Wireless SSID+Password settings and rest default..(I left the IP of modem as it is first, 192.168.1.1 and then set to 192.168.100.254 and 192.168.100.22 on subsequent trials..)

Motorola has only 1 real setting, which is to Enable the DHCP. (it says it has a DHCP Pool of 32.)
Modem IP is 192.168.100.1 and DHCP Pool is 100.2 via 100.42.

Now I got internet on my Desktop, but phone/tablet wireless connections stuck on acquiring IP...

So I am guessing they can't get IP from DHCP..

Weird part is, when I do ipconfig /all on my Desktop, I see totally different IP/Gateways (such as 24.133.220.75 as IP, 24.133.221.66 as gateway); which I assume are ISP's IP Addresses assigned to my connection...

So probably Motorola doesn't assign me IP at all.. (But why does it have DHCP Enabled option with a pool of 32 then?)

My Question:
Is there any way I can use the TD-W8951ND as a Router in this setup? Or do I need a Router with a WAN Port on it (which the 8951 doesn't have..)

Thanks for anyone helping me in this..